By "heating apparatus" is meant in general any apparatus, portable or otherwise, integrating or connected to a source of combustible gas, using the heat of combustion produced by the catalytic burner for various purposes, such as cooking, heating, soldering, generation of hot air, hair curling, etc., and possibly comprising other elements or members permitting the use of the apparatus for the purpose or intention adopted, for example a soldering-iron bit if the use adopted for the apparatus is soldering.
By "catalytic burner" is meant any assembly enabling a combustible gas to be burnt, by mixture of the latter with so-called primary air, upstream of a catalytic structure, flameless combustion of the said mixture during its passage through the catalytic structure and removal of the combustion exhaust gases via the downstream face of this same structure. Such a burner according to the invention, called "inducted-air" burner, should be distinguished from catalytic burners called "secondary-air" burners, for which the combustible gas passes directly through the catalytic structure, and is flamelessly burnt on the downstream face of the said catalytic structure, by mixing with ambient air.
By "catalytic structure" or "catalytic combustion structure" is meant any structure permeable to the mixture to be burnt and sufficiently thick to generate a pressure drop during the passage of the mixture from the upstream face to the downstream face of the said structure. This structure extends, in terms of surface, transversely or perpendicularly to the direction of passage of the mixture to be burnt. This structure comprises a support which is inert with respect to the mixture to be burnt, the combustible gas and combustion gases. This support is also mechanically able to withstand the high temperatures generated by the catalytic combustion. This support is coated, at least on its internal surface or surfaces, directly or indirectly, by a so-called catalytic material, such as platinum or platinum salts, which catalyze the combustion.
From the above definition emerge, on the one hand, the catalytic structures called "honeycomb" structures consisting of a slice or a core of a refractory material such as ceramic, traversed by a plurality of adjacent transverse channels and, on the other hand, structures of the catalytic gauze or fabric type.